1. Field of the Invention
This invention relates generally to aircraft windows and specifically the prevention of the fogging of windows.
2. Background of the Invention
Throughout the history of commercial aviation, airlines have experienced the severe fogging, or the formation of condensation, on passenger windows on their aircraft.
There are numerous potential causes of fogging on passenger windows. One such cause seems to be related to breather holes found on aircraft windows. As shown in FIGS. 1A and 1B, window assembly 100 has a breather hole or vent hole 102, usually located on the inner pane of window assembly 100. Breather hole 102 is typically designed to equalize pressure in cavity 104 between two structural window panes 106 and 108 in response to the pressure changes inside the aircraft cabin.
During normal operation of the aircraft, the vibration of window assembly 100 causes window panes 106 and 108 to vibrate, which can result in air pulsing in and out of breather hole 102. This pulsing air can carry unintended moist cabin air into window assembly 100 causing an undesirable fogging of the window. Testing of windows in the lab confirms that this pulsing of air can occur at typical aircraft vibration levels and can directly contribute to the window fogging.
Accordingly, what is needed is a device that allows slow moving air to pass and equalize pressure in the cavity, while preventing or significantly reducing the passage of the pulsing or non-steady air.